1. Field of the Invention
The present invention relates to an apparatus for forming a thin film. More particularly, the present invention relates to an apparatus capable of forming a thin film using an inkjet printing method.
2. Description of the Related Art
In general, an organic light emitting diode (OLED) has an organic light emitting layer formed between an anode electrode and a cathode electrode. Electrons from the anode electrode are combined with holes from the cathode electrode in the organic light emitting layer, so that molecules of the organic light emitting layer are in the excited state. When the excited molecules are changed into the ground state, the light is generated in the organic light emitting layer.
The OLED has various layers, such as a light emitting layer, a hole injection layer, a hole transport layer, an electron injection layer or an electron transport layer, etc. Usually, the layers for the OLED are formed using an organic material, and also formed by an inkjet printing method with an inkjet printing apparatus.
FIG. 1 is a schematic perspective view showing a conventional apparatus for forming a thin film.
Referring to FIG. 1, a conventional inkjet apparatus 50 has an inkjet printing chamber 10, a buffer chamber 20 and a drying chamber 30.
In the conventional inkjet printing apparatus 50, drying time for drying an organic material coated on a substrate is longer than printing time for coating the organic material on the substrate. Hence, a bottleneck phenomenon may occur while a thin film including the organic material is formed on the substrate.
Further, the drying chamber 30 has a plurality of substrate stages 40 so as to simultaneously dry a plurality of substrates on which the thin film is formed. However, the substrates loaded on the substrate stages 40 may not be dried simultaneously and completely. Thus, when the dried substrates are unloaded from the drying chamber 30 before all the substrates are completely dried, drying condition inside the drying chamber 30 may be rapidly changed, so that the substrates may be contaminated.
In order to prevent contamination of the substrates, when the substrates loaded into the drying chamber 30 are transferred to a next process chamber after the substrates are completely dried, throughput of the thin film forming process may be lowered.